IEC 61375-3-4:2014 specifies the data communication network inside a Consist based on Ethernet technology, the Ethernet Consist Network (ECN). The applicability of this part of IEC 61375 to the Consist Network allows for interoperability of individual vehicles within Open Trains in international traffic. This part of IEC 61375 may be additionally applicable to closed trains and Multiple Unit Trains when so agreed between purchaser and supplier.